Physics Physics is the branch of science that encompasses the natural world, including the earth and all of the physical systems within, as well as the universe and the mechanisms that govern everything. It is the fundamental science

The Kinetic Theory of Gases A Gas is composed of particles usually molecules or atoms. Between the particles is empty space. The particles are in constant random motion. They are moving in straight lines until they bounce off each other or the walls. All collisions are perfectly elastic Container

The Gas Laws 1. Boyle’s Law 2. Charles’ Law 3. Guy-Lussac Law Describe HOW gases behave. Can be predicted by the theory. Amount of change can be calculated with mathematical equations. 1. Boyle’s Law 2. Charles’ Law 3. Guy-Lussac Law 4. Avogadro’s Hypothesis

Boyle’s Law At a constant temperature pressure and volume are inversely related. P  1/V 1 atm 2 atm 2 Liters 4 Liters

Charles’ Law The volume of a gas is directly proportional to the temperature if the pressure is held constant. V  T 600 K 300 K

Gay Lussac’s Law The temperature and the pressure of a gas are directly related at constant volume. P  T 300 K 600 K

Avagadro’s Hypothesis V is proportional to number of molecules at constant T and P. V  n

The Ideal Gas Equation P x V = n x R x T Pressure times Volume equals the number of moles times the Ideal Gas Constant (R) times the temperature in Kelvin. This time R does not depend on anything, it is really constant R = 0.0821 (L atm)/(mol K)

The Average speed of an oxygen molecule is 1656 km/hr at 200C The molecules don’t travel very far without hitting each other so they move in random directions. Maxwell distribution of molecular speeds

Fundamental Forces

Michelson’s experiment

Gravitation Newton’s Law of Gravitation All objects in the Universe were attracted to each other in the same way the apple was attracted to the Earth

Free-Fall Acceleration and the Gravitational Force Consider an object of mass m near the Earth’s surface Acceleration ag due to gravity Since Near the Earth’s surface

Free-Fall Acceleration and the Gravitational Force Consider an object of mass m at a height h above the Earth’s surface Acceleration ag due to gravity ag will vary with altitude

Escape Speed The escape speed is the speed needed for an object to soar off into space and not return For the earth, vesc is about 11.2 km/s (40200 Km/h) Note, v is independent of the mass of the object The escape speeds for various members of the solar system Escape speed is one factor that determines a planet’s atmosphere

= 0 because the final v is zero = 0 because the final r is infinity

7.9 Km/s 11.2 Km/s

Black Hole video Link to Black Holes video

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